Methyl 4-nitrobenzenesulfonate Research Articles

Quantitative Determination of Four Potential Genotoxic Impurities in the Active Pharmaceutical Ingredients in TSD-1 Using UPLC-MS/MS.

A novel method of ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed for the identification and quantification of four potential genotoxic impurities (PGIs) in the active pharmaceutical ingredients of TSD-1, a novel P2Y12 receptor antagonist. Four PGIs were named, 4-nitrobenzenesulfonic acid, methyl 4-nitrobenzenesulfonate, ethyl 4-nitrobenzenesulfonate, and isopropyl 4-nitrobenzenesulfonate. Following the International Conference of Harmonization (ICH) guidelines, this methodology is capable of quantifying four PGIs at 15.0 ppm in samples of 0.5 mg/mL concentration. This validated approach presented very low limits (0.1512–0.3897 ng/mL), excellent linearity (coefficients > 0.9900), and a satisfactory recovery range (94.9–115.5%). The method was sufficient in terms of sensitivity, linearity, precision, accuracy, selectivity, and robustness and, thus, has high practicality in the pharmaceutical quality control of TSD-1.

Study of the reaction of methyl 4‐nitrobenzenesulfonate and Br− in water–glycerol cationic micellar solutions

AbstractThe reaction of methyl 4‐nitrobenzenesulfonate (MNB) and Br− has been studied in water–glycerol (GLY) alkyltrimethylammonium bromide micellar solutions, with the weight percentage of glycerol up to 50%. A pseudophase kinetic model was used for quantitatively discussing the kinetic data. Results showed that the equilibrium‐binding constant for the organic substrate molecules to the cationic micelles decreases upon increasing the amount of glycerol present in the micellar reaction media. The second‐order rate constant of the reaction in the micellar pseudophase is practically independent of wt% of GLY. Similar results were found in other water–organic solvent alkyltrimethylammonium bromide micellar solutions for the same process. However, the dependence of the reaction rate, for a given surfactant concentration, on the wt% of organic solvent is weaker for glycerol than for the other organic solvents. This was explained by considering that the cationic micellar ionization degree is nearly independent of wt% GLY. As a consequence, bromide ions concentration in the interfacial region (the reaction site) does not change by varying wt% of GLY. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 845–582, 2008

Study of the reaction between methyl 4-nitrobenzenesulfonate and bromide ions in mixed single-chain-gemini micellar solutions: Kinetic evidence for morphological transitions

The reaction between methyl 4-nitrobenzenesulfonate and bromide ions has been studied in mixed single-chain-gemini micellar solutions of n-dodecyltrimethylammonium bromide, DTAB, and dodecyl tricosaoxyethylene glycol ether, Brij 35, with alkanediyl- α- ω-bis(dodecyldimethylammonium) bromide, 12- s-12,2Br − ( s = 3 , 4 , 5 ). Kinetic micellar effects show that an increase in the solution mole fraction of the single-chain surfactant, X single - chain , results in a diminution of the mixed micelles tendency to form spherocylindrical aggregates upon increasing surfactant concentration. The dependence of the surfactant concentration at which the sphere-to-rod transition occurs, C ∗ , on X single - chain showed through kinetic data was in agreement with results obtained by means of fluorescence measurements.

Reaction of methyl 4-nitrobenzenesulfonate with Br- in water-formamide tetradecyltrimethylammonium bromide micellar solutions

The reaction methyl 4-nitrobenzenesulfonate + Br- was studied in water-formamide tetradecyltrimethylammonium bromide micellar solutions. A pseudophase kinetic model was used to quantitatively rationalize the kinetic micellar effects observed

Micellar Solutions of Sulfobetaine Surfactants in Water−Ethylene Glycol Mixtures: Surface Tension, Fluorescence, Spectroscopic, Conductometric, and Kinetic Studies

Micellization in water-ethylene glycol (EG) N-dodecyl, N-tetradecyl, and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SB3-12, SB3-14, and SB3-16, respectively) micellar solutions, with the weight percent of EG changing within the range 0-40, was studied by means of surface tension measurements. Information about the influence of the added EG on the aggregation number of the sulfobetaine micelles and on the polarity of the interfacial region of micelles was obtained through fluorescence and spectroscopic measurements. Surface tension measurements also provide information about the dependence of the surface excess concentration, the minimum area per surfactant molecule, the surface pressure at the cmc, and the standard Gibbs energy of adsorption on the added weight percent of the organic solvent. The Gordon parameter of the water-EG mixtures was also estimated by means of surface tension measurements. The thermodynamic and structural changes originated by the presence of EG control the micellar kinetic effects observed in the reaction methyl 4-nitrobenzenesulfonate + Br(-) occurring in the water-EG sulfobetaine micellar solutions. Information about the distribution of bromide ions between the bulk and micellar pseudophases was obtained through conductivity measurements. The kinetic micellar effects were quantitatively explained by using the pseudophase kinetic model.

Water−N,N-Dimethylformamide Alkyltrimethylammonium Bromide Micellar Solutions: Thermodynamic, Structural, and Kinetic Studies

Various amounts of N,N-dimethylformamide (DMF) with the weight percentage of DMF varying within the range 0-20, were added to aqueous micellar solutions of hexadecyl-, tetradecyl-, and dodecyltrimethylammonium bromides (CTAB, TTAB, and DTAB, respectively). Information about changes in the critical micelle concentrations, in the micellar ionization degrees, in the aggregation numbers, and in the polarity of the interfacial region of micelles upon changing the weight percent of DMF was obtained through conductivity and fluorescence measurements. Surface tension measurements permitted the estimation of the Gordon parameter of the water-DMF mixtures. The thermodynamic and structural changes provoked by the addition of DMF to the cationic micellar solutions were evidenced through the micellar kinetic effects observed in the reaction methyl 4-nitrobenzenesulfonate + Br-, investigated in the water-DMF cationic micellar solutions. The pseudophase kinetic model was adequate to quantitatively rationalize the dependence of the observed rate constant on surfactant concentration as well as on the weight percent of DMF.

Water−Ethylene Glycol Alkyltrimethylammonium Bromide Micellar Solutions as Reaction Media: Study of the Reaction Methyl 4-Nitrobenzenesulfonate + Br-

The SN2 substitution reaction between methyl 4-nitrobenzenesulfonate and bromide ions has been studied in several water−ethylene glycol, EG, cationic micellar solutions, the surfactants being hexadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and dodecyltrimethylammonium bromide. Together with the kinetic experiments, conductivity measurements gave information about the critical micelle concentration and the micellar ionization degree of the water−EG micellar solutions used as reaction media. They also permitted us to gain thermodynamic information about the influence of added EG on the micellization process of the surfactants investigated. A simple pseudophase model was shown to be useful in the discussion of the kinetic results. The importance of the working surfactant concentration range in the reliability of the adjustable parameters obtained from the fittings was stressed. It was found that the reaction was faster in cationic micelles than in water, in the absence as well as in the presence of ethylene glycol. The influence of the surfactant nature as well as of the ethylene glycol content on the equilibrium binding constant describing the distribution of the methyl 4-nitrobenzenesulfonate between the micellar and water−EG bulk phase and on the second-order rate constant for the reaction in the micellar pseudophase was rationalized by considering the polarity of the surface micellar region of the aggregates present in the different reaction media.

The Reaction Methyl 4-Nitrobenzenesulfonate + Br- in Cationic and Zwitterionic Micellar Solutions

The reaction methyl 4-nitrobenzenesulfonate + Br- was studied in tetradecyltrimethylammonium bromide aqueous solutions in the presence and absence of 0.1 M NaBr, as well as in N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SB3-14) micellar solutions in the presence of 0.1 M NaBr. Discussion of kinetic results in cationic micellar solutions was used to show some problems concerning the estimation of the second-order rate constants in the micellar pseudophases. The errors introduced by rationalizing the kinetic micellar effects in SB3-14 micellar solutions through pseudo-first-order rate constants were also shown; the contribution of the reaction occurring in the aqueous phase and the binding of the bromide ions to the sulfobetaine micelles were the cause of such errors. To complete the work, the influence of the cation coming from the added bromides on the micellar effects observed in SB3-14 micellar solutions was investigated. Results give information about how cations influence the bromide assoc...

Kinetic Studies of the Alkylation of Metal Cyanide Complexes: M(CO)x(L)5-xCN (M = Mn, Re) and CpM‘(CO)x(L)2-xCN (M‘ = Fe, Ru)

Reaction rates for the alkylation of Mn(CO)(dppm)(2)CN (dppm = PPh(2)CH(2)PPh(2)), Mn(CO)(2)(tripod)CN [tripod = (PPh(2)CH(2))(3)CCH(3)], Re(CO)(3)(dppm)CN, (eta(6)-C(6)Me(6))Mn(CO)(2)CN, CpFe(dppe)CN (dppe = PPh(2)CH(2)CH(2)PPh(2)), CpRu(dppe)CN, and CpRu(CO)(PPh(3))CN with methyl 4-nitrobenzenesulfonate (MeONs) to produce complexes of the type [L(n)()M-CNMe](+) (-)ONs were investigated in 1,2-dichloroethane (DCE) at 30.0 degrees C. The reactions are first order in both the complex and the alkylating agent, which is consistent with a mechanism that involves nucleophilic attack of the cyanide nitrogen on the methyl of the MeONs. The second-order rate constants (k(2)) correlate approximately with the stretching frequency of the cyanide ligand nu(CN) in the complexes. There is a somewhat better correlation between nu(CN) of the CNCH(3) ligands in the products and k(2). There is also a good correlation between the rate constant (k(2)) and the calculated force constant (k(CO)) for the nu(CO) vibrational mode of the analogous [L(n)()M-CO](+) complex. These correlations appear to be useful for predicting nucleophilicities of metal cyanide complexes of different metals, in different oxidation states, and with ligands exhibiting a range of electronic and steric properties.

Synthesis and characterization of poly(N-acyl orN-aroyl ethylenimines) containing various pendant functional groups. IV. Poly (N-aroylethylenimines) with allyloxy and 3-hydroxy propyloxy groups

4-Allyloxy phenyl oxazoline was polymerized using methyl 4-nitrobenzene sulfonate as an initiator (M/I = 100/1) in o-dichlorobenzene. The olefin group in the resulting polymer, PAPO, was quantitatively transformed to a (SINGLE BOND)CH2 (SINGLE BOND)CH2 (SINGLE BOND)OH group by (1) hydroborating the olefin group using 9-BBN as a hydroborating agent in CHCl3/THF, and (2) oxidizing the hydroborated polymer. The polymer backbone is very stable in the hydroboration and oxidation environment. Both PAPO and the hydroxylated polymer, PAPO-OH, are crystalline and show birefringence. The PAPO-OH polymer crystallizes slowly due to its bulky side chain and strong interference of hydroxyl group with the packing of polymer molecules. However, once the polymer crystallizes, the side chains are extended and the (SINGLE BOND)OH groups do not hydrogen bond with the carbonyl groups in the polymer backbone. © 1996 John Wiley & Sons, Inc.

Synthesis and characterization of poly(N-acyl orN-aroyl ethylenimines) containing various pendant functional groups. I. Copolymers with pendant olefin groups

Decenyl (D) and heptyl (H) oxazolines were copolymerized in o-dichlorobenzene solvent using methyl 4-nitrobenzenesulfonate as an initiator. A series of decenyl/heptyl oxazolines random copolymers (or DH copolymers) with a total degree of polymerization of 100 and narrow molecular weight distribution were obtained. These copolymers are considered as the poly(N-acylethylenimine)s with allyl pendant groups randomly attached to the far end of their polymethylene, (SINGLE BOND)(CH2)7(SINGLE BOND), side chains. The polymers were characterized by NMR, FT–IR. Both DSC and x-ray diffractometer demonstrated that the polymers are highly crystalline. © 1996 John Wiley & Sons, Inc.

Nucleophilicity towards a saturated carbon atom: rate constants for the aminolysis of methyl 4-nitrobenzenesulfonate in aqueous solution. A comparison of the n and N + parameters for amine nucleophilicity

Second-order rate constants (kNu) have been measured in aqueous solution (I= 0.1 mol dm –3, 25 °C) for the SN2 reactions of methyl 4-nitrobenzenesulfonate with ammonia, 41 primary amines, 20 secondary amines. 29 tertiary amines and 7 anionic nucleophiles. For the aminolysis reactions, Brønsted-type correlations of nucleophilicity with basicity require the classification of all amines in terms of strictly defined structural classes with βnuc in the range 0.15–0.39. Swain–Scott plots indicate that simple amines, water and other light-atom nucleophiles (hydroxide, azide and cyanide, anions) are five times more reactive than heavy-atom nucleophiles (thiosulfate, thiocyanate, iodide and bromide ions). For amine nucleophiles there is a close linear correlation (of slope 0.44, and including both primary and secondary amines) between log kNu for the aminolysis of methyl 4-nitrobenzenesulfonate and log kNu for amine addition to the 1-methyl-4-vinylpyridinium cation. This correlation demonstrates a close linear relationship between the Swain–Scott n parameter and Ritchie's N+parameter for amine nucleophiles in aqueous solution (N+= 2.1n– 4.3).